The present invention relates to a valve timing control apparatus for variably controlling opening and closing timings of an engine valve, i.e., an intake valve and an exhaust valve, of an internal combustion engine depending on operating conditions of the engine.
Such a valve timing control apparatus is so designed as to control the opening and closing timings of the engine valve by varying a relative rotational phase of a crankshaft and a camshaft. The relative rotational phase of the crankshaft and the camshaft is adjusted by operating a phase adjustor. The phase adjustor is disposed between a drive rotary member operatively coupled with the crankshaft and a driven rotary member disposed on the camshaft side. Recently, there have been proposed various kinds of phase adjustors utilizing a gearing including a helical gear, a linkage or the like. The phase adjustor using the linkage is advantageous in lessening an axial length of the phase adjustor and reducing friction loss thereof.
Japanese Patent Application First Publication No. 2001-41013 discloses a valve timing control apparatus including such a phase adjustor using the linkage. FIGS. 14 and 15 show the valve timing control apparatus of the related art. As illustrated in FIGS. 14 and 15, housing 101 as a drive rotary member is rotatably fitted onto an end portion of camshaft 102. Housing 101 is drivably connected to an engine crankshaft via a timing chain. A plurality of followers 104 are slidably engaged in radial guide grooves 103 formed in an axial end surface of housing 101. Lever shaft 106 as a driven rotary member is mounted to the end portion of camshaft 102. A plurality of levers 105 radially outward projecting from lever shaft 106 are connected with the corresponding followers 104 via links 107. Levers 105 and followers 104 are pivotally supported at opposite ends of links 107, respectively. Intermediate rotary member 109 is disposed in opposed relation to the axial end surface of housing 101 in which radial guide grooves,103 are formed, and supported on inner support rod 113 so as to be rotatable relative to housing 101 and lever shaft 106. Intermediate rotary member 109 has spiral guide groove 108 in the end surface opposed to radial guide grooves 103. A plurality of arcuate projections 110 projecting from an axial end face of each of followers 104 are engaged with spiral guide groove 108 and guided therealong. When electromagnetic brake 112 is deenergized, intermediate rotary member 109 is biased by spring 111 to be urged toward an advanced rotational position. In this position, followers 104 are placed at the radially outer-most position in the respective radial guide grooves 103, in which the relative rotational phase between housing 101 and camshaft 102 is held most retarded or most advanced. Further, when electromagnetic brake 112 is energized, intermediate rotary member 109 is decelerated by the action of electromagnetic brake 112 toward a retarded rotational position. In this position, followers 104 are moved to the radially inner position, so that the relative rotational phase between housing 101 and camshaft 102 is held most advanced or most retarded. Lubricating oil supply passage 120 extends along camshaft 102 and is open to an axial end face of camshaft 102. Lubricating oil is supplied to links 107 and mutually engaging portions of followers 104 and spiral guide grooves 108 via lubricating oil supply passage 120.
In such a valve timing control apparatus as described above, the lubricating oil flows outside from the clearance between housing 101 and intermediate rotary member 109 so that links 107 and the mutually engaging portions of followers 104 and spiral guide grooves 108 are not always immersed in the lubricating oil. Therefore, there is a demand to ensure sufficient lubrication at links 107 and the mutually engaging portions of followers 104 and spiral guide grooves 108. In addition, slight clearances are formed between the pivotal connections of links 107 to levers 105 and between the mutually engaging portions of followers 104 and spiral guide grooves 108 for the purpose of obtaining smooth motions thereof. There is a demand to prevent occurrence of vibration and noise at the slight clearances.
In one aspect of the present invention, there is provided a valve timing control apparatus for an internal combustion engine, comprising:
a drive rotary member adapted to be rotatively coupled with the engine;
a driven rotary member rotatably coupled with the drive rotary member;
an intermediate rotary member arranged to be rotatable relative to the drive rotary member and the driven rotary member;
a radial guide extending on one of the drive rotary member and the driven rotary member in a radial direction thereof;
a spiral guide disposed on the intermediate rotary member in an opposed relation to the radial guide;
a follower moveably engaged with the radial guide and the spiral guide;
a link coupling the follower with a radially outer periphery of the other of the drive rotary member and the driven rotary member, the link comprising one end pivotally connected with the radially outer periphery of the other of the drive rotary member and the driven rotary member and an opposite end pivotally connected with the follower;
an actuator operative to rotate the intermediate rotary member so as to allow a movement of the follower along the radial guide which is converted into relative rotation of the drive rotary member and the driven rotary member via the link; and
a lubricating oil chamber arranged to surround an engagement portion between the spiral guide and the follower and pivotal connection portions between the one end of the link and the radially outer periphery of the other of the drive rotary member and the driven rotary member and between the opposite end of the link and the follower, the lubricating oil chamber being adapted to be filled with lubricating oil.
In a further aspect of the present invention, there is provided a valve timing control apparatus for an internal combustion engine, comprising:
a drive rotary member adapted to be rotatively coupled with the engine;
a driven rotary member rotatably coupled with the drive rotary member;
an intermediate rotary member arranged to be rotatable relative to the drive rotary member and the driven rotary member;
a radial guide extending on one of the drive rotary member and the driven rotary member in a radial direction thereof;
a spiral guide disposed on the intermediate rotary member in an opposed relation to the radial guide;
a follower moveably engaged with the radial guide and the spiral guide;
a link coupling the follower with a radially outer periphery of the other of the drive rotary member and the driven rotary member, the link comprising one end pivotally connected with the radially outer periphery of the other of the drive rotary member and the driven rotary member and an opposite end pivotally connected with the follower;
an actuator operative to rotate the intermediate rotary member so as to allow a movement of the follower along the radial guide which is converted into relative rotation of the drive rotary member and the driven rotary member via the link; and
a lubricating oil chamber arranged to surround an engagement portion between the spiral guide and the follower and pivotal connection portions between the one end of the link and the radially outer periphery of the other of the drive rotary member and the driven rotary member and between the opposite end of the link and the follower, the lubricating oil chamber being adapted to be filled with lubricating oil and supplied with an amount of lubricating oil larger than an amount of lubricating oil leaking therefrom.
In a still further aspect of the present invention, there is provided a valve timing control apparatus for an internal combustion engine, comprising:
a drive rotary member adapted to be rotatively coupled with the engine;
a driven rotary member rotatably coupled with the drive rotary member;
an intermediate rotary member arranged to be rotatable relative to the drive rotary member and the driven rotary member;
phase adjusting linkage means for coupling the drive rotary member and the driven rotary member and adjusting a relative rotational phase of the drive rotary member and the driven rotary member;
actuator means for operating the intermediate rotary member to allow the adjustment of the relative rotational phase via the phase adjusting linkage means; and
wall means for defining a lubricating oil chamber in cooperation with the intermediate rotary member and one of the drive rotary member and the driven rotary member, the phase adjusting linkage means is disposed within the lubricating oil chamber.
Other objects and features of this invention will become understood from the following description with reference to the accompanying drawings.